Re Mike's OPE-L:939, also sequentialism and the revaluation of
inputs in general:

To avoid taking up so much space on the airwaves, I'd like to
consider carefully all the points made by Fred, John and
Andrew, and others who have come in on this debate, in a
considered contribution in a couple of weeks. Till then I'll
lay off the sequential question and concentrate on value
conservation. So don't take it as rude if I'm absent the while
from the sequentialism debate (tho' it seems to be proceeding
fine)

Till then I would hope that OPE members look more carefully
about the numerical examples I've provided. Here I list the
points which I would hope are considered carefully. The next
and separate post concerns the way texts are interpreted, in
the light of these (and other) discussions about contradiction
and consistency.

The questions are:

(i) When is the 'current period'
================================
There is, to say the least, an open question about *when* in
the 'current period' the 'socially-necessary labour-time' is
calculated. Once agreed (as, I am glad to see, Fred does) that
value is a social average and not the most up-to-date method,
it has to be accepted that 'replacement value' is not constant
throughout the period. Because, as the second corn example
shows, the relative volume of goods produced using backward and
advanced techniques changes throughout the period.

I deliberately highlighted this in an extremal case (which Marx
himself discusses) in which all the corn from the previous
harvest is consumed before the corn from the current harvest
emerges. In this case, the (average) value of corn is a step
function. At one point in the current period (the beginning) it
is given by the value arising from the previous harvest,
because only corn from the previous harvest is in existence. At
another point also in the current period (the end) the value is
given by the value arising from the current harvest, because
*no* corn from the previous harvest is in existence.

Thus the phrase used by Fred and others "in the current period"
has no unique meaning. This has to be resolved. *When* in the
current period? We say - in this extremal case - the point where
the inputs cease to exist (hence, as Marx says, revaluations affect
'existing' stocks). The standard interpretation (the only one which
makes it legitimate to write down a simultaneous equation) says, at
the point when the outputs have all emerged. What do you say?

(ii) by the way, how long is a current period?
==============================================

[nasty one this. Please think about it. The answer is not simple]

(iii)How do stocks enter the determination of value? (or price)
===============================================================
If one does not take the extremal case (or impose an arbitrary
fixed length on the 'period') one has to allow for stocks.
Thus, if some of the harvest of the previous year is kept in
existence while the new harvest is reaped, then the value of
corn must change not all at once but gradually as the harvest
comes in; and moreover the new average will depend on the
volume of stocks and its ratio to the volume of current
production.

Alternatively, if we divide what we consider to be the 'period'
in half, and assume that at the beginning of what we previously
treated as the period, sufficient constant capital is purchased
to last this entire period, we then find on subdividing the
period, that a portion of constant capital is not consumed
in its entirety but persists as stocks.

In either case, stocks must be considered.

Again, there *is* no single unique 'current value' to go into
the simultaneous equation. A more fundamental analysis is required.
And, if you *literally* apply the 'standard interpretation' you
arrive at absurd contradictions, as I showed, such as infinite
value, value arising out of nowhere, and even (in the case of a
severe harvest failure) negative values.

(iv) What is a stock?
====================
What, if any, is the *qualitative* difference between buffer
stocks (including work-in-progress) and fixed capital? Is it
not more coherent and logical (and simpler) to treat buffer stocks,
work in progress, and fixed capital, with Marx, all as particular
forms of constant capital with different turnovers, rather than as
distinct forms of capital in their own right? And hence to accept
that all these partipate in the same averaging process no matter
where they are on the circuit of capital?

In which case, we arrive - I think it can be shown - at a
completely consistent account of moral depreciation, tying in
with the other aspects of Marx's account of value.